Exclusive: Inside Christina Aguilera's AMA Performance!

Christina Aguilera is hard at work rehearsing for her big performance at the 2012 American Music Awards on Sunday – and Access Hollywood has the exclusive details on what the pop diva will perform.

The superstar singer will treat fans to a medley of new songs off of her latest album, “Lotus,” including, “Let There Be Love,” “Army of Me” and “Lotus,” a source inside Christina’s closed AMA rehearsal revealed to Access on Saturday.

“The Voice” coach will begin her performance in a pink dress, before vanishing for about one minute in, then reemerging rocking a glittering black bustier.

Christina’s performance will feature an anti-bullying theme, the source said, with her dancers dressed as misfits (including bikers, drag queens, etc.), and carrying signs featuring words associated with bullying, such as “doubt,” “hate” and “fear.”

Catch Christina’s performance (along with performances by Psy, Carly Rae Jespen, Kelly Clarkson, The Wanted and more) on the 2012 American Music Awards – Sunday at 8/7c on ABC.